1. Field of the Invention
The present invention relates to a human interface device, and more particularly, to a human interface device using a time divisional two-way communication method, and a wireless communication method thereof.
2. Description of Related Art
A human interface device refers to anything that serves as an interface between a human and a computer or peripheral device such as a keyboard, a mouse, a wireless sensor, a mobile phone, a notebook computer, a digital camera, etc.
Human interface devices are gradually adopting wireless communication technology in order to maximize user convenience. Such a human interface device is comprised of a wireless input unit 2 performing an operation based on a user's request and generating operation data, and a host digital terminal 1 connected to a computer 3 via cable and to the wireless input unit 2 wirelessly, for interfacing between the computer 3 and the wireless input unit 2.
The host digital terminal 1 establishes an occupancy channel and an emergency channel to wirelessly communicate with the wireless input unit 2, receives data from the wireless input unit 2 through the occupancy channel in normal operation, converts the received data into a format recognized by the computer 3, and provides the converted data to the computer 3. Further, when there is interference such as cross-talk or noise on the occupancy channel, the host digital terminal 1 detects the interference and provides the wireless input unit 2 with data to establish a new occupancy channel, through the emergency channel.
The wireless input unit 2 establishes an occupancy channel and an emergency channel to wirelessly communicate with the host digital terminal 1, performs an operation based on the user's request in normal operation, and upon occurrence of operation data, transmits the operation data to the host digital terminal 1 over the occupancy channel. Further, when there is interference such as cross-talk or noise on the occupancy channel, the wireless input unit 2 receives data to establish a new occupancy channel, through the emergency channel, and establishes a new occupancy channel accordingly.
FIG. 2 is a diagram illustrating channels for performing wireless communication in a conventional human interface device.
Referring to FIG. 2, the conventional human interface device employing a frequency division scheme includes a plurality of channels CH1-CHN which use different frequency bands, including a transmission channel TX CH and a reception channel RX CH per a channel.
Further, one channel CH1 of the plurality of channels CH1-CHN is used as an emergency channel for communicating data to establish a new occupancy channel, and another channel CH3, for example, is used as an occupancy channel to communicate operation data.
In normal operation, the wireless input unit 2 transmits operation data generated as a result of an operation to the host digital terminal 1 through the transmission channel TX CH of the occupancy channel CH3, and the host digital terminal 1 receives the operation data of the wireless input unit 2 through the transmission channel RX CH of the occupancy channel CH3.
However, a main operation of the human interface device is to transmit data from the wireless input unit 2 to the host digital terminal 1. Accordingly, while the transmission channel TX CH of the occupancy channel CH3 is mainly used, the reception channel RX CH of the occupancy channel CH3 is rarely used, so that a frequency bandwidth corresponding to the reception channel RX CH of the occupancy CH3 channel is wasted.
Further, in order for the host digital terminal 1 and the wireless input unit 2 to communicate wirelessly, they should be able to simultaneously recognize different frequency bands corresponding to the transmission channel TX CH and reception channel RX CH, respectively.
So, the host digital terminal 1 and the wireless input unit 2 have to further include a duplexer unit for separating and selecting frequency bands of the transmission and reception channels through a band pass filtering operation, and separately include a unit for modulating data on the transmission channel and a unit for demodulating data on the reception channel.
As such, since the conventional human interface device employs the frequency division scheme, there is a problem in that it has to include a duplexer unit, a unit for modulating data on the transmission channel, and a unit for demodulating data on the reception channel, while wasting frequency bandwidth, and thus production cost and product size increase.